Winner of the Diamond Jubilee Stakes at Royal Ascot, the four-year-old produced a scintillating display when breaking the Newmarket track record in the July Cup.
Having won a leg of the Global Sprint Challenge, the flying grey would have been eligible for a huge bonus if he did head Down Under and was successful in the Patinack Farm Classic at Flemington on November 9.
Connections suggested shortly after his July Cup victory that an Australian mission was under serious consideration.
However, with Lethal Force having since suffered defeat at the hands of Moonlight Cloud in the Prix Maurice de Gheest at Deauville, Cox has decided against the trip across the globe.
“We were very grateful for the invitation but after lots of consideration, we have decided going to Australia looks a very difficult trip for the horse to encounter, so we’ve declined,” said the Lambourn handler.
“The horse is having a break after his run at Deauville last weekend. He’s already had a very successful season, winning two Group Ones and finishing second in another.
“We’re happy with where we are with the horse and I’m keeping an open mind about where he’ll go from here.”
While a trip to Australia may be out, there is still a chance Lethal Force will be boarding a long-haul flight before the year is out, with the Breeders’ Cup Sprint under serious consideration.
Cox does not envisage the turning six-furlong trip at Santa Anita being a problem for his charge.
“We are very much confident he is one of the best sprinters around and if he is giving us the impression that he is still in the same form as he has been in this summer, then we would have to consider it (the Breeders’ Cup),” said Cox.
“I don’t see any reason why it (Santa Anita) would be a problem for him, he’s a very well balanced horse.”
Meanwhile connections of Telescope are keen to let the dust settle on his slightly disappointing display in Saturday’s Rose Of Lancaster Stakes before committing to future targets.
Harry Herbert, racing manager for owners Highclere Thoroughbred Racing, is confident all is not lost.
Herbert said: “I haven’t spoken to Michael (Stoute) this morning. We agreed we’d speak on Monday unless something noteworthy came up, so no news is normally good news. We were disappointed he didn’t appear to fire as we had hoped and like he does at home, but hopefully there is still a long way to go with the horse.”